Contact over active gate structures with etch stop layers for advanced integrated circuit structure fabrication

ABSTRACT

Contact over active gate (COAG) structures with etch stop layers, and methods of fabricating contact over active gate (COAG) structures using etch stop layers, are described. In an example, an integrated circuit structure includes a plurality of gate structures above substrate, each of the gate structures including a gate insulating layer thereon. A plurality of conductive trench contact structures is alternating with the plurality of gate structures, each of the conductive trench contact structures including a trench insulating layer thereon. A first dielectric etch stop layer is directly on and continuous over the trench insulating layers and the gate insulating layers. A second dielectric etch stop layer is directly on and continuous over the first dielectric etch stop layer, the second dielectric etch stop layer distinct from the first dielectric etch stop layer. An interlayer dielectric material is on the second dielectric etch stop layer.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a division of U.S. patent application Ser. No.16/147,541, filed on Sep. 28, 2018, the entire contents of which ishereby incorporated by reference herein.

TECHNICAL FIELD

Embodiments of the disclosure are in the field of advanced integratedcircuit structure fabrication and, in particular, 10 nanometer node andsmaller integrated circuit structure fabrication and the resultingstructures.

BACKGROUND

For the past several decades, the scaling of features in integratedcircuits has been a driving force behind an ever-growing semiconductorindustry. Scaling to smaller and smaller features enables increaseddensities of functional units on the limited real estate ofsemiconductor chips. For example, shrinking transistor size allows forthe incorporation of an increased number of memory or logic devices on achip, lending to the fabrication of products with increased capacity.The drive for ever-more capacity, however, is not without issue. Thenecessity to optimize the performance of each device becomesincreasingly significant.

Variability in conventional and currently known fabrication processesmay limit the possibility to further extend them into the 10 nanometernode or sub-10 nanometer node range. Consequently, fabrication of thefunctional components needed for future technology nodes may require theintroduction of new methodologies or the integration of new technologiesin current fabrication processes or in place of current fabricationprocesses.

In the manufacture of integrated circuit devices, multi-gatetransistors, such as tri-gate transistors, have become more prevalent asdevice dimensions continue to scale down. Tri-gate transistors aregenerally fabricated on either bulk silicon substrates orsilicon-on-insulator substrates. In some instances, bulk siliconsubstrates are preferred due to their lower cost and compatibility withthe existing high-yielding bulk silicon substrate infrastructure.

Scaling multi-gate transistors has not been without consequence,however. As the dimensions of these fundamental building blocks ofmicroelectronic circuitry are reduced and as the sheer number offundamental building blocks fabricated in a given region is increased,the constraints on the semiconductor processes used to fabricate thesebuilding blocks have become overwhelming.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A illustrates a plan view of a semiconductor device having a gatecontact disposed over an inactive portion of a gate electrode. FIG. 1Billustrates a cross-sectional view of a non-planar semiconductor devicehaving a gate contact disposed over an inactive portion of a gateelectrode.

FIG. 2A illustrates a plan view of a semiconductor device having a gatecontact via disposed over an active portion of a gate electrode, inaccordance with an embodiment of the present disclosure. FIG. 2Billustrates a cross-sectional view of a non-planar semiconductor devicehaving a gate contact via disposed over an active portion of a gateelectrode, in accordance with an embodiment of the present disclosure.

FIGS. 3A-3D illustrate cross-sectional views illustrating variousoperations in a method of fabricating a contact over active gate (COAG)structures having an etch stop layers, in accordance with an embodimentof the present disclosure.

FIGS. 4A-4D illustrate cross-sectional views representing variousoperations in a method of fabricating a semiconductor structure having agate contact structure disposed over an active portion of a gate, inaccordance with an embodiment of the present disclosure.

FIG. 5 illustrates a plan view and corresponding cross-sectional viewsof an integrated circuit structure having trench contacts including anoverlying insulating cap layer, in accordance with an embodiment of thepresent disclosure.

FIGS. 6A-6F illustrate cross-sectional views of various integratedcircuit structures, each having trench contacts including an overlyinginsulating cap layer and having gate stacks including an overlyinginsulating cap layer, in accordance with an embodiment of the presentdisclosure.

FIG. 7A illustrates a plan view of another semiconductor device having agate contact via disposed over an active portion of a gate, inaccordance with another embodiment of the present disclosure.

FIG. 7B illustrates a plan view of another semiconductor device having atrench contact via coupling a pair of trench contacts, in accordancewith another embodiment of the present disclosure.

FIGS. 8A-8F illustrate cross-sectional views representing variousoperations in a method of fabricating an integrated circuit structurewith a gate stack having an overlying insulating cap layer, inaccordance with an embodiment of the present disclosure.

FIG. 9 illustrates a computing device in accordance with oneimplementation of the disclosure.

FIG. 10 illustrates an interposer that includes one or more embodimentsof the disclosure.

FIG. 11 is an isometric view of a mobile computing platform employing anIC fabricated according to one or more processes described herein orincluding one or more features described herein, in accordance with anembodiment of the present disclosure.

FIG. 12 illustrates a cross-sectional view of a flip-chip mounted die,in accordance with an embodiment of the present disclosure.

DESCRIPTION OF THE EMBODIMENTS

Contact over active gate (COAG) structures with etch stop layers, andmethods of fabricating contact over active gate (COAG) structures usingetch stop layers, are described. In the following description, numerousspecific details are set forth, such as specific integration andmaterial regimes, in order to provide a thorough understanding ofembodiments of the present disclosure. It will be apparent to oneskilled in the art that embodiments of the present disclosure may bepracticed without these specific details. In other instances, well-knownfeatures, such as integrated circuit design layouts, are not describedin detail in order to not unnecessarily obscure embodiments of thepresent disclosure. Furthermore, it is to be appreciated that thevarious embodiments shown in the Figures are illustrativerepresentations and are not necessarily drawn to scale.

The following detailed description is merely illustrative in nature andis not intended to limit the embodiments of the subject matter or theapplication and uses of such embodiments. As used herein, the word“exemplary” means “serving as an example, instance, or illustration.”Any implementation described herein as exemplary is not necessarily tobe construed as preferred or advantageous over other implementations.Furthermore, there is no intention to be bound by any expressed orimplied theory presented in the preceding technical field, background,brief summary or the following detailed description.

This specification includes references to “one embodiment” or “anembodiment.” The appearances of the phrases “in one embodiment” or “inan embodiment” do not necessarily refer to the same embodiment.Particular features, structures, or characteristics may be combined inany suitable manner consistent with this disclosure.

Terminology. The following paragraphs provide definitions or context forterms found in this disclosure (including the appended claims):

“Comprising.” This term is open-ended. As used in the appended claims,this term does not foreclose additional structure or operations.

“Configured To.” Various units or components may be described or claimedas “configured to” perform a task or tasks. In such contexts,“configured to” is used to connote structure by indicating that theunits or components include structure that performs those task or tasksduring operation. As such, the unit or component can be said to beconfigured to perform the task even when the specified unit or componentis not currently operational (e.g., is not on or active). Reciting thata unit or circuit or component is “configured to” perform one or moretasks is expressly intended not to invoke 35 U.S.C. § 112, sixthparagraph, for that unit or component.

“First,” “Second,” etc. As used herein, these terms are used as labelsfor nouns that they precede, and do not imply any type of ordering(e.g., spatial, temporal, logical, etc.).

“Coupled”—The following description refers to elements or nodes orfeatures being “coupled” together. As used herein, unless expresslystated otherwise, “coupled” means that one element or node or feature isdirectly or indirectly joined to (or directly or indirectly communicateswith) another element or node or feature, and not necessarilymechanically.

In addition, certain terminology may also be used in the followingdescription for the purpose of reference only, and thus are not intendedto be limiting. For example, terms such as “upper”, “lower”, “above”,and “below” refer to directions in the drawings to which reference ismade. Terms such as “front”, “back”, “rear”, “side”, “outboard”, and“inboard” describe the orientation or location or both of portions ofthe component within a consistent but arbitrary frame of reference whichis made clear by reference to the text and the associated drawingsdescribing the component under discussion. Such terminology may includethe words specifically mentioned above, derivatives thereof, and wordsof similar import.

“Inhibit”—As used herein, inhibit is used to describe a reducing orminimizing effect. When a component or feature is described asinhibiting an action, motion, or condition it may completely prevent theresult or outcome or future state completely. Additionally, “inhibit”can also refer to a reduction or lessening of the outcome, performance,or effect which might otherwise occur. Accordingly, when a component,element, or feature is referred to as inhibiting a result or state, itneed not completely prevent or eliminate the result or state.

Embodiments described herein may be directed to front-end-of-line (FEOL)semiconductor processing and structures. FEOL is the first portion ofintegrated circuit (IC) fabrication where the individual devices (e.g.,transistors, capacitors, resistors, etc.) are patterned in thesemiconductor substrate or layer. FEOL generally covers everything up to(but not including) the deposition of metal interconnect layers.Following the last FEOL operation, the result is typically a wafer withisolated transistors (e.g., without any wires).

Embodiments described herein may be directed to back end of line (BEOL)semiconductor processing and structures. BEOL is the second portion ofIC fabrication where the individual devices (e.g., transistors,capacitors, resistors, etc.) get interconnected with wiring on thewafer, e.g., the metallization layer or layers. BEOL includes contacts,insulating layers (dielectrics), metal levels, and bonding sites forchip-to-package connections. In the BEOL part of the fabrication stagecontacts (pads), interconnect wires, vias and dielectric structures areformed. For modern IC processes, more than 10 metal layers may be addedin the BEOL.

Embodiments described below may be applicable to FEOL processing andstructures, BEOL processing and structures, or both FEOL and BEOLprocessing and structures. In particular, although an exemplaryprocessing scheme may be illustrated using a FEOL processing scenario,such approaches may also be applicable to BEOL processing. Likewise,although an exemplary processing scheme may be illustrated using a BEOLprocessing scenario, such approaches may also be applicable to FEOLprocessing.

In accordance with an embodiment of the present disclosure, contact overactive gate (COAG) structures and processes are described. One or moreembodiments of the present disclosure are directed to semiconductorstructures or devices having one or more gate contact structures (e.g.,as gate contact vias) disposed over active portions of gate electrodesof the semiconductor structures or devices. One or more embodiments ofthe present disclosure are directed to methods of fabricatingsemiconductor structures or devices having one or more gate contactstructures formed over active portions of gate electrodes of thesemiconductor structures or devices. Approaches described herein may beused to reduce a standard cell area by enabling gate contact formationover active gate regions. In one or more embodiments, the gate contactstructures fabricated to contact the gate electrodes are self-alignedvia structures.

In technologies where space and layout constraints are somewhat relaxedcompared with current generation space and layout constraints, a contactto gate structure may be fabricated by making contact to a portion ofthe gate electrode disposed over an isolation region. As an example,FIG. 1A illustrates a plan view of a semiconductor device having a gatecontact disposed over an inactive portion of a gate electrode.

Referring to FIG. 1A, a semiconductor structure or device 100A includesa diffusion or active region 104 disposed in a substrate 102, and withinan isolation region 106. One or more gate lines (also known as polylines), such as gate lines 108A, 108B and 108C are disposed over thediffusion or active region 104 as well as over a portion of theisolation region 106. Source or drain contacts (also known as trenchcontacts), such as contacts 110A and 110B, are disposed over source anddrain regions of the semiconductor structure or device 100A. Trenchcontact vias 112A and 112B provide contact to trench contacts 110A and110B, respectively. A separate gate contact 114, and overlying gatecontact via 116, provides contact to gate line 108B. In contrast to thesource or drain trench contacts 110A or 110B, the gate contact 114 isdisposed, from a plan view perspective, over isolation region 106, butnot over diffusion or active region 104. Furthermore, neither the gatecontact 114 nor gate contact via 116 is disposed between the source ordrain trench contacts 110A and 110B.

FIG. 1B illustrates a cross-sectional view of a non-planar semiconductordevice having a gate contact disposed over an inactive portion of a gateelectrode. Referring to FIG. 1B, a semiconductor structure or device100B, e.g. a non-planar version of device 100A of FIG. 1A, includes anon-planar diffusion or active region 104C (e.g., a fin structure)formed from substrate 102, and within isolation region 106. Gate line108B is disposed over the non-planar diffusion or active region 104B aswell as over a portion of the isolation region 106. As shown, gate line108B includes a gate electrode 150 and gate dielectric layer 152, alongwith a dielectric cap layer 154. Gate contact 114, and overlying gatecontact via 116 are also seen from this perspective, along with anoverlying metal interconnect 160, all of which are disposed ininter-layer dielectric stacks or layers 170. Also seen from theperspective of FIG. 1B, the gate contact 114 is disposed over isolationregion 106, but not over non-planar diffusion or active region 104B.

Referring again to FIGS. 1A and 1B, the arrangement of semiconductorstructure or device 100A and 100B, respectively, places the gate contactover isolation regions. Such an arrangement wastes layout space.However, placing the gate contact over active regions would requireeither an extremely tight registration budget or gate dimensions wouldhave to increase to provide enough space to land the gate contact.Furthermore, historically, contact to gate over diffusion regions hasbeen avoided for risk of drilling through other gate material (e.g.,polysilicon) and contacting the underlying active region. One or moreembodiments described herein address the above issues by providingfeasible approaches, and the resulting structures, to fabricatingcontact structures that contact portions of a gate electrode formed overa diffusion or active region.

As an example, FIG. 2A illustrates a plan view of a semiconductor devicehaving a gate contact via disposed over an active portion of a gateelectrode, in accordance with an embodiment of the present disclosure.Referring to FIG. 2A, a semiconductor structure or device 200A includesa diffusion or active region 204 disposed in a substrate 202, and withinan isolation region 206. One or more gate lines, such as gate lines208A, 208B and 208C are disposed over the diffusion or active region 204as well as over a portion of the isolation region 206. Source or draintrench contacts, such as trench contacts 210A and 210B, are disposedover source and drain regions of the semiconductor structure or device200A. Trench contact vias 212A and 212B provide contact to trenchcontacts 210A and 210B, respectively. A gate contact via 216, with nointervening separate gate contact layer, provides contact to gate line208B. In contrast to FIG. 1A, the gate contact 216 is disposed, from aplan view perspective, over the diffusion or active region 204 andbetween the source or drain contacts 210A and 210B.

FIG. 2B illustrates a cross-sectional view of a non-planar semiconductordevice having a gate contact via disposed over an active portion of agate electrode, in accordance with an embodiment of the presentdisclosure. Referring to FIG. 2B, a semiconductor structure or device200B, e.g. a non-planar version of device 200A of FIG. 2A, includes anon-planar diffusion or active region 204B (e.g., a fin structure)formed from substrate 202, and within isolation region 206. Gate line208B is disposed over the non-planar diffusion or active region 204B aswell as over a portion of the isolation region 206. As shown, gate line208B includes a gate electrode 250 and gate dielectric layer 252, alongwith a dielectric cap layer 254. The gate contact via 216 is also seenfrom this perspective, along with an overlying metal interconnect 260,both of which are disposed in inter-layer dielectric stacks or layers270. Also seen from the perspective of FIG. 2B, the gate contact via 216is disposed over non-planar diffusion or active region 204B.

Thus, referring again to FIGS. 2A and 2B, in an embodiment, trenchcontact vias 212A, 212B and gate contact via 216 are formed in a samelayer and are essentially co-planar. In comparison to FIGS. 1A and 1B,the contact to the gate line would otherwise include and additional gatecontact layer, e.g., which could be run perpendicular to thecorresponding gate line. In the structure(s) described in associationwith FIGS. 2A and 2B, however, the fabrication of structures 200A and200B, respectively, enables the landing of a contact directly from ametal interconnect layer on an active gate portion without shorting toadjacent source drain regions. In an embodiment, such an arrangementprovides a large area reduction in circuit layout by eliminating theneed to extend transistor gates on isolation to form a reliable contact.As used throughout, in an embodiment, reference to an active portion ofa gate refers to that portion of a gate line or structure disposed over(from a plan view perspective) an active or diffusion region of anunderlying substrate. In an embodiment, reference to an inactive portionof a gate refers to that portion of a gate line or structure disposedover (from a plan view perspective) an isolation region of an underlyingsubstrate.

In an embodiment, the semiconductor structure or device 200 is anon-planar device such as, but not limited to, a fin-FET or a tri-gatedevice. In such an embodiment, a corresponding semiconducting channelregion is composed of or is formed in a three-dimensional body. In onesuch embodiment, the gate electrode stacks of gate lines 208A and 208Bsurround at least a top surface and a pair of sidewalls of thethree-dimensional body. In another embodiment, at least the channelregion is made to be a discrete three-dimensional body, such as in agate-all-around device. In one such embodiment, the gate electrodestacks of gate lines 208A and 208B each completely surrounds the channelregion.

Generally, one or more embodiments are directed to approaches for, andstructures formed from, landing a gate contact via directly on an activetransistor gate. Such approaches may eliminate the need for extension ofa gate line on isolation for contact purposes. Such approaches may alsoeliminate the need for a separate gate contact (GCN) layer to conductsignals from a gate line or structure. In an embodiment, eliminating theabove features is achieved by recessing contact metals in a trenchcontact (TCN) and introducing an additional dielectric material in theprocess flow (e.g., trench insulating layer (TILA)). The additionaldielectric material is included as a trench contact dielectric cap layerwith etch characteristics different from the gate dielectric materialcap layer used for trench contact alignment in a gate aligned contactprocess (GAP) processing scheme (e.g., use of a gate insulating layer(GILA)).

In accordance with one or more embodiments of the present disclosure,etch stop layers stacks are implemented to provide for improved viacontact selectivity to TILA/GILA and for substantially improved yield.In an embodiment, a via opening etch lands on an upper dielectric etchstop layer with very high selectivity. The upper dielectric etch stoplayer is etched with selectivity to an underlying lower dielectric etchstop layer. The lower dielectric etch stop layer is then etched toexpose underlying TILA/GILA regions. The multi-operation breakthroughprocess may be implemented to reduce loss to the underlying TILA/GILAregions and enable significant yield improvement.

As an exemplary fabrication scheme, FIGS. 3A-3D illustratecross-sectional views illustrating various operations in a method offabricating a contact over active gate (COAG) structures having an etchstop layers, in accordance with an embodiment of the present disclosure.

Referring to FIG. 3A, a plurality of gate structures 304 is formed abovea fin or substrate 302. Gate structures 304 may include a gatedielectric and gate electrode. Each of the gate structures 304 includesa gate insulating layer (GILA) 306 or gate dielectric cap thereon.Dielectric spacers 307 may be along sidewalls of the each gate stack304/GILA 306 pairing. The gate structures 304 alternate with conductivetrench contact structures 308. Each of the conductive trench contactstructures 308 includes a trench insulating layer (TILA) 310 or contactdielectric cap thereon. A first dielectric etch stop layer 312 isdirectly on and is continuous over the trench insulating layers 310 andthe gate insulating layers 306 and, possibly, the dielectric spacers307. A second dielectric etch stop layer 314 is directly on andcontinuous over the first dielectric etch stop layer 312. The seconddielectric etch stop layer 314 is distinct from the first dielectricetch stop layer 312. An interlayer dielectric (ILD) material 316 is onthe second dielectric etch stop layer 314.

Referring again to FIG. 3A, an opening 318 is formed in the ILD material316. The opening 318 may include a trench portion 320 and a via portion322. In an embodiment, opening 318 is formed in ILD material 316 usingdry or plasma etch process. The etch process stops on the seconddielectric etch stop layer 314. In one embodiment, the etch used to formopening 318 lands with greater than 10:1, and preferably more than 20:1selectivity to the second dielectric etch stop layer 314. In doing so,there is minimal to no loss or erosion of TILA/GILA structures as aresult of the etch process used to form opening 318. Also, there isminimal to no loss or erosion of TILA/GILA structures as a result ofcleans processes subsequently used to clean opening 318 prior to furtherprocessing, where such cleans processes may otherwise undesirablyoxidize TILA/GILA surfaces.

Referring to FIG. 3B, the via portion 322 of opening 318 is extendedthrough the second dielectric etch stop layer 314 to form opening 318Ahaving via portion 322A and patterned second dielectric etch stop layer314A.

Referring to FIG. 3C, The via portion 322A of opening 318A is thenextended through the first dielectric etch stop layer 312 to formopening 318B having via portion 322B and patterned first dielectric etchstop layer 312A. In one embodiment, the via opening 322B extends into(e.g., removes) one of the TILA structures 310 to expose a correspondingone of the trench contact structures 308, as is depicted, for subsequentelectrical contact formation. In another embodiment, not depicted, thevia opening 322B extends into (e.g., removes) one of the GILA structures306 to expose a corresponding one of the gate structures 304, forsubsequent electrical contact formation.

In an embodiment, via portion 322B of opening 318B is formed in a singledry or plasma etch process that both forms patterned first dielectricetch stop layer 312A and removes the targeted TILA structure 310 (orGILA structure 306). In another embodiment, via portion 322B of opening318B is formed using a first dry or plasma etch process to formpatterned first dielectric etch stop layer 312A, followed by a seconddry or plasma etch process that removes the targeted TILA structure 310(or GILA structure 306). It is to be appreciated that formation of viaopening 322B may not remove the one of the TILA structures 310 withperfect selectivity to other exposed materials. For example, dielectricspacer erosion may occur to form eroded dielectric spacers 307A. Erosionmay also extend into a neighboring GILA structure 306, as is depicted.Nonetheless, in accordance with embodiments of the present disclosure,such erosion is substantially mitigated by a process involving first 312and second 314 dielectric etch stop layers, as compared with a processthat does not involve use of first 312 and second 314 dielectric etchstop layers.

Referring to FIG. 3D, a conductive structure 350 is formed in opening318B. In an embodiment, conductive structure 350 includes an upperconductive line or interconnect and a lower conductive via.

Referring to FIGS. 3A-3D, in an embodiment, ILD material 316 is a low-kmaterial. In a particular embodiment, ILD material 316 is a carbon dopedoxide (CDO) material which may also be referred to as a SiOCH film,since the material includes silicon, oxygen, carbon and hydrogen. In anembodiment, opening 318 is formed in ILD material 316 using afluorine-based dry or plasma etch process.

In an embodiment, second etch stop layer 314 is highly resistant to thefluorine-based dry or plasma etch process used to form opening 322 inILD material 316. In an embodiment, the second etch stop layer 314includes a metal oxide material. In one such embodiment, the metal oxidematerial is an aluminum oxide material. In a particular such embodiment,the second etch stop layer 314 includes approximately 35-40 atomic %aluminum and 60-65 atomic % oxygen. Impurities may also be included,such as 0.5-1 atomic percent hydrogen and 0.1-0.5 atomic % carbon. In anembodiment, the second etch stop layer 314 is an aluminum oxide materialformed using atomic deposition (ALD) with trimethylaluminum (TMA) andwater as precursors. In an embodiment, the second etch stop layer 314 isan amorphous material layer. In an embodiment, the second etch stoplayer 314 has a thickness in the range of 20-120 Angstroms.

In an embodiment, second etch stop layer 314 is etchable by a highlyselective wet etch process, such as a wet etch process involving use ofa glycol ether, a cyclic amine, a glycol, an amine, or a combination oftwo or more thereof. Not to be bound by theory, in an embodiment, thesecond etch stop layer 314 becomes surface-fluorinated during thefluorine-based dry or plasma etch process used to form opening 318. Uponexposure to the wet etch, HF may be formed as a very localized etchantfor patterning the second etch stop layer 314. It is to be appreciatedthat use of an aluminum oxide as a metal oxide material for second etchstop layer 314 may have superior wet etch characteristics as comparedagainst other metal oxides (such as titanium oxide, hafnium oxide orzirconium oxide) which have proven difficult to wet etch.

In an embodiment, first etch stop layer 312 is highly resistant to thewet etch process used to pattern second dielectric etch stop layer 314.In an embodiment, the first etch stop layer 312 includes a siliconnitride material. In one such embodiment, the silicon nitride materialhas a lower dielectric constant than the metal oxide material of thesecond dielectric etch stop layer 314. In a particular such embodiment,the first etch stop layer 312 includes approximately 40-50 atomic %nitrogen, 30-40 atomic % silicon, and 10-20 atomic % hydrogen.Impurities may also be included, such as 1-2 atomic percent oxygen. Inan embodiment, the first etch stop layer 312 is an amorphous materiallayer. In an embodiment, the first etch stop layer 312 has a thicknessin the range of 50-150 Angstroms.

In an embodiment, GILA structures 306 underlying the first dielectricetch stop layer 312 are composed of a silicon nitride material having adifferent composition than a silicon nitride material of the first etchstop layer 312. In one such embodiment, GILA structures 306 are anamorphous silicon nitride material including approximately 50-55 atomic% nitrogen, 35-40 atomic % silicon, and 5-10 atomic % hydrogen.Impurities may also be included, such as 0.1-0.3 atomic percent oxygenand/or around 0.1% carbon. In an embodiment, the TILA structures 310underlying the first dielectric etch stop layer 312 are composed of asilicon carbide material, such as a silicon carbide material formed in ahigh density plasma tool.

As another exemplary fabrication scheme, FIGS. 4A-4D illustratecross-sectional views representing various operations in a method offabricating a semiconductor structure having a gate contact structuredisposed over an active portion of a gate, in accordance with anembodiment of the present disclosure.

Referring to FIG. 4A, a semiconductor structure 400 is providedfollowing trench contact (TCN) formation. It is to be appreciated thatthe specific arrangement of structure 400 is used for illustrationpurposes only, and that a variety of possible layouts may benefit fromembodiments of the disclosure described herein. The semiconductorstructure 400 includes one or more gate stack structures, such as gatestack structures 408A-408E disposed above a substrate 402. The gatestack structures may include a gate dielectric layer and a gateelectrode. Trench contacts, e.g., contacts to diffusion regions ofsubstrate 402, such as trench contacts 410A-410C are also included instructure 400 and are spaced apart from gate stack structures 408A-408Eby dielectric spacers 420. An insulating cap layer 422 may be disposedon the gate stack structures 408A-408E (e.g., GILA), as is also depictedin FIG. 4A. As is also depicted in FIG. 4A, contact blocking regions or“contact plugs,” such as region 423 fabricated from an inter-layerdielectric material, may be included in regions where contact formationis to be blocked.

In an embodiment, providing structure 400 involves formation of acontact pattern which is essentially perfectly aligned to an existinggate pattern while eliminating the use of a lithographic operation withexceedingly tight registration budget. In one such embodiment, thisapproach enables the use of intrinsically highly selective wet etching(e.g., versus dry or plasma etching) to generate contact openings. In anembodiment, a contact pattern is formed by utilizing an existing gatepattern in combination with a contact plug lithography operation. In onesuch embodiment, the approach enables elimination of the need for anotherwise critical lithography operation to generate a contact pattern,as used in other approaches. In an embodiment, a trench contact grid isnot separately patterned, but is rather formed between poly (gate)lines. For example, in one such embodiment, a trench contact grid isformed subsequent to gate grating patterning but prior to gate gratingcuts.

Furthermore, the gate stack structures 408A-408E may be fabricated by areplacement gate process. In such a scheme, dummy gate material such aspolysilicon or silicon nitride pillar material, may be removed andreplaced with permanent gate electrode material. In one such embodiment,a permanent gate dielectric layer is also formed in this process, asopposed to being carried through from earlier processing. In anembodiment, dummy gates are removed by a dry etch or wet etch process.In one embodiment, dummy gates are composed of polycrystalline siliconor amorphous silicon and are removed with a dry etch process includingSF₆. In another embodiment, dummy gates are composed of polycrystallinesilicon or amorphous silicon and are removed with a wet etch processincluding aqueous NH₄OH or tetramethylammonium hydroxide. In oneembodiment, dummy gates are composed of silicon nitride and are removedwith a wet etch including aqueous phosphoric acid.

In an embodiment, one or more approaches described herein contemplateessentially a dummy and replacement gate process in combination with adummy and replacement contact process to arrive at structure 400. In onesuch embodiment, the replacement contact process is performed after thereplacement gate process to allow high temperature anneal of at least aportion of the permanent gate stack. For example, in a specific suchembodiment, an anneal of at least a portion of the permanent gatestructures, e.g., after a gate dielectric layer is formed, is performedat a temperature greater than approximately 600 degrees Celsius. Theanneal is performed prior to formation of the permanent contacts.

Referring to FIG. 4B, the trench contacts 410A-410C of the structure 400are recessed within spacers 420 to provide recessed trench contacts411A-411C that have a height below the top surface of spacers 420 andinsulating cap layer 422. An insulating cap layer 424 is then formed onrecessed trench contacts 411A-411C (e.g., TILA). In accordance with anembodiment of the present disclosure, the insulating cap layer 424 onrecessed trench contacts 411A-411C is composed of a material having adifferent etch characteristic than insulating cap layer 422 on gatestack structures 408A-408E. As will be seen in subsequent processingoperations, such a difference may be exploited to etch one of 422/424selectively from the other of 422/424.

The trench contacts 410A-410C may be recessed by a process selective tothe materials of spacers 420 and insulating cap layer 422. For example,in one embodiment, the trench contacts 410A-410C are recessed by an etchprocess such as a wet etch process or dry etch process. Insulating caplayer 424 may be formed by a process suitable to provide a conformal andsealing layer above the exposed portions of trench contacts 410A-410C.For example, in one embodiment, insulating cap layer 424 is formed by achemical vapor deposition (CVD) process as a conformal layer above theentire structure. The conformal layer is then planarized, e.g., bychemical mechanical polishing (CMP), to provide insulating cap layer 424material only above trench contacts 410A-410C, and re-exposing spacers420 and insulating cap layer 422.

Regarding suitable material combinations for insulating cap layers422/424, in one embodiment, one of the pair of 422/424 is composed ofsilicon oxide while the other is composed of silicon nitride. In anotherembodiment, one of the pair of 422/424 is composed of silicon oxidewhile the other is composed of carbon doped silicon nitride. In anotherembodiment, one of the pair of 422/424 is composed of silicon oxidewhile the other is composed of silicon carbide. In another embodiment,one of the pair of 422/424 is composed of silicon nitride while theother is composed of carbon doped silicon nitride. In anotherembodiment, one of the pair of 422/424 is composed of silicon nitridewhile the other is composed of silicon carbide. In another embodiment,one of the pair of 422/424 is composed of carbon doped silicon nitridewhile the other is composed of silicon carbide.

Referring to FIG. 4C, a first dielectric etch stop layer 450 (such asdescribed in association with first dielectric etch stop layer 312) anda second dielectric etch stop layer 452 (such as described inassociation with second dielectric etch stop layer 314) are formed overthe structure of FIG. 4B. An inter-layer dielectric (ILD) 430 andhardmask 432 stack are then formed and patterned to provide, e.g., ametal (0) trench 434 patterned above the structure of FIG. 4B.

The inter-layer dielectric (ILD) 430 may be composed of a materialsuitable to electrically isolate metal features ultimately formedtherein while maintaining a robust structure between front end and backend processing. Furthermore, in an embodiment, the composition of theILD 430 is selected to be consistent with via etch selectivity fortrench contact dielectric cap layer patterning, as described in greaterdetail below in association with FIG. 4D. In one embodiment, the ILD 430is composed of a single or several layers of silicon oxide or a singleor several layers of a carbon doped oxide (CDO) material. However, inother embodiments, the ILD 430 has a bi-layer composition with a topportion composed of a different material than an underlying bottomportion of the ILD 430. The hardmask layer 432 may be composed of amaterial suitable to act as a subsequent sacrificial layer. For example,in one embodiment, the hardmask layer 432 is composed substantially ofcarbon, e.g., as a layer of cross-linked organic polymer. In otherembodiments, a silicon nitride or carbon-doped silicon nitride layer isused as a hardmask 432. The inter-layer dielectric (ILD) 430 andhardmask 432 stack may be patterned by a lithography and etch process.

Referring to FIG. 4D, via openings 436 (e.g., VCT) are formed ininter-layer dielectric (ILD) 430, extending from metal (0) trench 434 toone or more of the recessed trench contacts 411A-411C. The via openings436 may be formed using a multiple-etch process in which seconddielectric etch stop layer 452 and first dielectric etch stop layer 450are sequentially patterned to form a second patterned dielectric etchstop layer 452A and a first patterned dielectric etch stop layer 450A.

For example, in FIG. 4D, via openings are formed to expose recessedtrench contacts 411A and 411C. The formation of via openings 436includes etching of both inter-layer dielectric (ILD) 430 and respectiveportions of corresponding insulating cap layer 424. In one suchembodiment, a portion of insulating cap layer 422 is exposed duringpatterning of inter-layer dielectric (ILD) 430 (e.g., a portion ofinsulating cap layer 422 over gate stack structures 408B and 408E isexposed). In that embodiment, insulating cap layer 424 is etched to formvia openings 436 selective to (i.e., without significantly etching orimpacting) insulating cap layer 422.

In one embodiment, a via opening pattern is ultimately transferred tothe insulating cap layer 424 (i.e., the trench contact insulating caplayers) by an etch process without etching the insulating cap layer 422(i.e., the gate insulating cap layers). The insulating cap layer 424(TILA) may be composed of any of the following or a combinationincluding silicon oxide, silicon nitride, silicon carbide, carbon dopedsilicon nitrides, carbon doped silicon oxides, amorphous silicon,various metal oxides and silicates including zirconium oxide, hafniumoxide, lanthanum oxide or a combination thereof. The layer may bedeposited using any of the following techniques including CVD, ALD,PECVD, PVD, HDP assisted CVD, low temperature CVD. A correspondingplasma dry etch is developed as a combination of chemical and physicalsputtering mechanisms. Coincident polymer deposition may be used tocontrol material removal rate, etch profiles and film selectivity. Thedry etch is typically generated with a mix of gases that include NF₃,CHF₃, C₄F₈, HBr and O₂ with typically pressures in the range of 30-100mTorr and a plasma bias of 50-1000 Watts. The dry etch may be engineeredto achieve significant etch selectivity between cap layer 424 (TILA) and422 (GILA) layers to minimize the loss of 422 (GILA) during dry etch of424 (TILA) to form contacts to the source drain regions of thetransistor.

Referring again to FIG. 4D, it is to be appreciated that a similarapproach may be implemented to fabricate a via opening pattern that isultimately transferred to the insulating cap layer 422 (i.e., the trenchcontact insulating cap layers) by an etch process without etching theinsulating cap layer 424 (i.e., the gate insulating cap layers).

To further exemplify concepts of a contact over active gate (COAG)technology, FIG. 5 illustrates a plan view and correspondingcross-sectional views of an integrated circuit structure having trenchcontacts including an overlying insulating cap layer, in accordance withan embodiment of the present disclosure.

Referring to FIG. 5, an integrated circuit structure 500 includes a gateline 504 above a semiconductor substrate or fin 502, such as a siliconfin. The gate line 504 includes a gate stack 505 (e.g., including a gatedielectric layer or stack and a gate electrode on the gate dielectriclayer or stack) and a gate insulating cap layer 506 on the gate stack505. Dielectric spacers 508 are along sidewalls of the gate stack 505and, in an embodiment, along sidewalls of the gate insulating cap layer506, as is depicted.

Trench contacts 510 are adjacent the sidewalls of the gate line 504,with the dielectric spacers 508 between the gate line 504 and the trenchcontacts 510. Individual ones of the trench contacts 510 include aconductive contact structure 511 and a trench contact insulating caplayer 512 on the conductive contact structure 511.

Referring again to FIG. 5, a gate contact via 514 is formed in anopening of the gate insulating cap layer 506 and electrically contactsthe gate stack 505. In an embodiment, the gate contact via 514electrically contacts the gate stack 505 at a location over thesemiconductor substrate or fin 502 and laterally between the trenchcontacts 510, as is depicted. In one such embodiment, the trench contactinsulating cap layer 512 on the conductive contact structure 511prevents gate to source shorting or gate to drain shorting by the gatecontact via 514.

Referring again to FIG. 5, trench contact vias 516 are formed in anopening of the trench contact insulating cap layer 512 and electricallycontact the respective conductive contact structures 511. In anembodiment, the trench contact vias 516 electrically contact therespective conductive contact structures 511 at locations over thesemiconductor substrate or fin 502 and laterally adjacent the gate stack505 of the gate line 504, as is depicted. In one such embodiment, thegate insulating cap layer 506 on the gate stack 505 prevents source togate shorting or drain to gate shorting by the trench contact vias 516.

It is to be appreciated that differing structural relationships betweenan insulating gate cap layer and an insulating trench contact cap layermay be fabricated. As examples, FIGS. 6A-6F illustrate cross-sectionalviews of various integrated circuit structures, each having trenchcontacts including an overlying insulating cap layer and having gatestacks including an overlying insulating cap layer, in accordance withan embodiment of the present disclosure.

Referring to FIGS. 6A, 6B and 6C, integrated circuit structures 600A,600B and 600C, respectively, includes a fin 602, such as a silicon fin.Although depicted as a cross-sectional view, it is to be appreciatedthat the fin 602 has a top 602A and sidewalls (into and out of the pageof the perspective shown). First 604 and second 606 gate dielectriclayers are over the top 602A of the fin 602 and laterally adjacent thesidewalls of the fin 602. First 608 and second 610 gate electrodes areover the first 604 and second 606 gate dielectric layers, respectively,over the top 602A of the fin 602 and laterally adjacent the sidewalls ofthe fin 602. The first 608 and second 610 gate electrodes each include aconformal conductive layer 609A. such as a workfunction-setting layer,and a conductive fill material 609B above the conformal conductive layer609A. The first 608 and second 610 gate electrodes both have a firstside 612 and a second side 614 opposite the first side 612. The first608 and second 610 gate electrodes also both have an insulating cap 616having a top surface 618.

A first dielectric spacer 620 is adjacent the first side 612 of thefirst gate electrode 608. A second dielectric spacer 622 is adjacent thesecond side 614 of the second gate electrode 610. A semiconductor sourceor drain region 624 is adjacent the first 620 and second 622 dielectricspacers. A trench contact structure 626 is over the semiconductor sourceor drain region 624 adjacent the first 620 and second 622 dielectricspacers.

The trench contact structure 626 includes an insulating cap 628 on aconductive structure 630. The insulating cap 628 of the trench contactstructure 626 has a top surface 629 substantially co-planar with a topsurfaces 618 of the insulating caps 616 of the first 608 and second 610gate electrodes. In an embodiment, the insulating cap 628 of the trenchcontact structure 626 extends laterally into recesses 632 in the first620 and second 622 dielectric spacers. In such an embodiment, theinsulating cap 628 of the trench contact structure 626 overhangs theconductive structure 630 of the trench contact structure 626. In otherembodiments, however, the insulating cap 628 of the trench contactstructure 626 does not extend laterally into recesses 632 in the first620 and second 622 dielectric spacers and, hence, does not overhang theconductive structure 630 of the trench contact structure 626.

It is to be appreciated that the conductive structure 630 of the trenchcontact structure 626 may not be rectangular, as depicted in FIGS.6A-6C. For example, the conductive structure 630 of the trench contactstructure 626 may have a cross-sectional geometry similar to or the sameas the geometry shown for conductive structure 630A illustrated in theprojection of FIG. 6A.

In an embodiment, the insulating cap 628 of the trench contact structure626 has a composition different than a composition of the insulatingcaps 616 of the first 608 and second 610 gate electrodes. In one suchembodiment, the insulating cap 628 of the trench contact structure 626includes a carbide material, such as a silicon carbide material. Theinsulating caps 616 of the first 608 and second 610 gate electrodesinclude a nitride material, such as a silicon nitride material.

In an embodiment, the insulating caps 616 of the first 608 and second610 gate electrodes both have a bottom surface 617A below a bottomsurface 628A of the insulating cap 628 of the trench contact structure626, as is depicted in FIG. 6A. In another embodiment, the insulatingcaps 616 of the first 608 and second 610 gate electrodes both have abottom surface 617B substantially co-planar with a bottom surface 628Bof the insulating cap 628 of the trench contact structure 626, as isdepicted in FIG. 6B. In another embodiment, the insulating caps 616 ofthe first 608 and second 610 gate electrodes both have a bottom surface617C above a bottom surface 628C of the insulating cap 628 of the trenchcontact structure 626, as is depicted in FIG. 6C.

In an embodiment, the conductive structure 630 of the trench contactstructure 628 includes a U-shaped metal layer 634, a T-shaped metallayer 636 on and over the entirety of the U-shaped metal layer 634, anda third metal layer 638 on the T-shaped metal layer 636. The insulatingcap 628 of the trench contact structure 626 is on the third metal layer638. In one such embodiment, the third metal layer 638 and the U-shapedmetal layer 634 include titanium, and the T-shaped metal layer 636includes cobalt. In a particular such embodiment, the T-shaped metallayer 636 further includes carbon.

In an embodiment, a metal silicide layer 640 is directly between theconductive structure 630 of the trench contact structure 626 and thesemiconductor source or drain region 624. In one such embodiment, themetal silicide layer 640 includes titanium and silicon. In a particularsuch embodiment, the semiconductor source or drain region 624 is anN-type semiconductor source or drain region. In another embodiment, themetal silicide layer 640 includes nickel, platinum and silicon. In aparticular such embodiment, the semiconductor source or drain region 624is a P-type semiconductor source or drain region. In another particularsuch embodiment, the metal silicide layer further includes germanium.

In an embodiment, referring to FIG. 6D, a conductive via 650 is on andelectrically connected to a portion of the first gate electrode 608 overthe top 602A of the fin 602. The conductive via 650 is in an opening ina first dielectric etch stop layer 650 (such as described in associationwith first dielectric etch stop layer 312) and a second dielectric etchstop layer 652 (such as described in association with second dielectricetch stop layer 314) and further into an opening 652 in the insulatingcap 616 of the first gate electrode 608. In one such embodiment, theconductive via 650 is on a portion of the insulating cap 628 of thetrench contact structure 626 but is not electrically connected to theconductive structure 630 of the trench contact structure 626. In aparticular such embodiment, the conductive via 650 is in an erodedportion 654 of the insulating cap 628 of the trench contact structure626.

In an embodiment, referring to FIG. 6E, a conductive via 660 is on andelectrically connected to a portion of the trench contact structure 626.The conductive via is in an opening in a first dielectric etch stoplayer 650 (such as described in association with first dielectric etchstop layer 312) and a second dielectric etch stop layer 652 (such asdescribed in association with second dielectric etch stop layer 314) anfurther in an opening 662 of the insulating cap 628 of the trenchcontact structure 626. In one such embodiment, the conductive via 660 ison a portion of the insulating caps 616 of the first 608 and second 610gate electrodes but is not electrically connected to the first 608 andsecond 610 gate electrodes. In a particular such embodiment, theconductive via 660 is in an eroded portion 664 of the insulating caps616 of the first 608 and second 610 gate electrodes.

Referring again to FIG. 6E, in an embodiment, the conductive via 660 isa second conductive via in a same structure as the conductive via 650 ofFIG. 6D. In one such embodiment, such a second conductive via 660 isisolated from the conductive via 650. In another such embodiment, suchas second conductive via 660 is merged with the conductive via 650 toform an electrically shorting contact 670, as is depicted in FIG. 6F.

The approaches and structures described herein may enable formation ofother structures or devices that were not possible or difficult tofabricate using other methodologies. In a first example, FIG. 7Aillustrates a plan view of another semiconductor device having a gatecontact via disposed over an active portion of a gate, in accordancewith another embodiment of the present disclosure. Referring to FIG. 7A,a semiconductor structure or device 700 includes a plurality of gatestructures 708A-708C interdigitated with a plurality of trench contacts710A and 710B (these features are disposed above an active region of asubstrate, not shown). A gate contact via 780 is formed on an activeportion the gate structure 708B. The gate contact via 780 is furtherdisposed on the active portion of the gate structure 708C, coupling gatestructures 708B and 708C. It is to be appreciated that the interveningtrench contact 710B may be isolated from the contact 780 by using atrench contact isolation cap layer (e.g., TILA). The contactconfiguration of FIG. 7A may provide an easier approach to strappingadjacent gate lines in a layout, without the need to route the strapthrough upper layers of metallization, hence enabling smaller cell areasor less intricate wiring schemes, or both.

In a second example, FIG. 7B illustrates a plan view of anothersemiconductor device having a trench contact via coupling a pair oftrench contacts, in accordance with another embodiment of the presentdisclosure. Referring to FIG. 7B, a semiconductor structure or device750 includes a plurality of gate structures 758A-758C interdigitatedwith a plurality of trench contacts 760A and 760B (these features aredisposed above an active region of a substrate, not shown). A trenchcontact via 790 is formed on the trench contact 760A. The trench contactvia 790 is further disposed on the trench contact 760B, coupling trenchcontacts 760A and 760B. It is to be appreciated that the interveninggate structure 758B may be isolated from the trench contact via 790 byusing a gate isolation cap layer (e.g., by a GILA process). The contactconfiguration of FIG. 7B may provide an easier approach to strappingadjacent trench contacts in a layout, without the need to route thestrap through upper layers of metallization, hence enabling smaller cellareas or less intricate wiring schemes, or both.

An insulating cap layer for a gate electrode may be fabricated usingseveral deposition operations and, as a result, may include artifacts ofa multi-deposition fabrication process. As an example, FIGS. 8A-8Fillustrate cross-sectional views representing various operations in amethod of fabricating an integrated circuit structure with a gate stackhaving an overlying insulating cap layer, in accordance with anembodiment of the present disclosure.

Referring to FIG. 8A, a starting structure 800 includes a gate stack 804above a substrate or fin 802. The gate stack 804 includes a gatedielectric layer 806, a conformal conductive layer 808, and a conductivefill material 810. In an embodiment, the gate dielectric layer 806 is ahigh-k gate dielectric layer formed using an atomic layer deposition(ALD) process, and the conformal conductive layer is a workfunctionlayer formed using an ALD process. In one such embodiment, a thermal orchemical oxide layer 812, such as a thermal or chemical silicon dioxideor silicon oxide layer, is between the substrate or fin 802 and the gatedielectric layer 806. Dielectric spacers 814, such as silicon nitridespacers, are adjacent sidewalls of the gate stack 804. The dielectricgate stack 804 and the dielectric spacers 814 are housed in aninter-layer-dielectric (ILD) layer 816. In an embodiment, the gate stack804 is formed using a replacement gate and replacement gate dielectricprocessing scheme. A mask 818 is patterned above the gate stack 804 andILD layer 816 to provide an opening 820 exposing the gate stack 804.

Referring to FIG. 8B, using a selective etch process or processes, thegate stack 804, including gate dielectric layer 806, conformalconductive layer 808, and conductive fill material 810, are recessedrelative to dielectric spacers 814 and layer 816. Mask 818 is thenremoved. The recessing provides a cavity 822 above a recessed gate stack824.

In another embodiment, not depicted, conformal conductive layer 808 andconductive fill material 810 are recessed relative to dielectric spacers814 and layer 816, but gate dielectric layer 806 is not recessed or isonly minimally recessed. It is to be appreciated that, in otherembodiments, a maskless approach based on high etch selectivity is usedfor the recessing.

Referring to FIG. 8C, a first deposition process in a multi-depositionprocess for fabricating a gate insulating cap layer is performed. Thefirst deposition process is used to form a first insulating layer 826conformal with the structure of FIG. 8B. In an embodiment, the firstinsulating layer 826 includes silicon and nitrogen, e.g., the firstinsulating layer 826 is a silicon nitride (Si₃N₄) layer, a silicon richsilicon nitride layer, a silicon-poor silicon nitride layer, or acarbon-doped silicon nitride layer. In an embodiment, the firstinsulating layer 826 only partially fills the cavity 822 above therecessed gate stack 824, as is depicted.

Referring to FIG. 8D, the first insulating layer 826 is subjected to anetch-back process, such as an anisotropic etch process, to provide firstportions 828 of an insulating cap layer. The first portions 828 of aninsulating cap layer only partially fill the cavity 822 above therecessed gate stack 824.

Referring to FIG. 8E, additional alternating deposition processes andetch-back processes are performed until cavity 822 is filled with aninsulating gate cap structure 830 above the recessed gate stack 824.Seams 832 may be evident in cross-sectional analysis and may beindicative of the number of alternating deposition processes andetch-back processes used to insulating gate cap structure 830. In theexample shown in FIG. 8E, the presence of three sets of seams 832A, 832Band 832C is indicative of four alternating deposition processes andetch-back processes used to insulating gate cap structure 830. In anembodiment, the material 830A, 830B, 830C and 830D of insulating gatecap structure 830 separated by seams 832 all have exactly orsubstantially the same composition.

Referring to FIG. 8F, a first dielectric etch stop layer 850 (such asdescribed in association with first dielectric etch stop layer 312) isformed on the structure of FIG. 8E. A second dielectric etch stop layer852 (such as described in association with second dielectric etch stoplayer 314) is formed on the first dielectric etch stop layer 850.

As described throughout the present application, a substrate may becomposed of a semiconductor material that can withstand a manufacturingprocess and in which charge can migrate. In an embodiment, a substrateis described herein is a bulk substrate composed of a crystallinesilicon, silicon/germanium or germanium layer doped with a chargecarrier, such as but not limited to phosphorus, arsenic, boron or acombination thereof, to form an active region. In one embodiment, theconcentration of silicon atoms in such a bulk substrate is greater than97%. In another embodiment, a bulk substrate is composed of an epitaxiallayer grown atop a distinct crystalline substrate, e.g. a siliconepitaxial layer grown atop a boron-doped bulk silicon mono-crystallinesubstrate. A bulk substrate may alternatively be composed of a groupIII-V material. In an embodiment, a bulk substrate is composed of aIII-V material such as, but not limited to, gallium nitride, galliumphosphide, gallium arsenide, indium phosphide, indium antimonide, indiumgallium arsenide, aluminum gallium arsenide, indium gallium phosphide,or a combination thereof. In one embodiment, a bulk substrate iscomposed of a III-V material and the charge-carrier dopant impurityatoms are ones such as, but not limited to, carbon, silicon, germanium,oxygen, sulfur, selenium or tellurium.

As described throughout the present application, isolation regions suchas shallow trench isolation regions or sub-fin isolation regions may becomposed of a material suitable to ultimately electrically isolate, orcontribute to the isolation of, portions of a permanent gate structurefrom an underlying bulk substrate or to isolate active regions formedwithin an underlying bulk substrate, such as isolating fin activeregions. For example, in one embodiment, an isolation region is composedof one or more layers of a dielectric material such as, but not limitedto, silicon dioxide, silicon oxy-nitride, silicon nitride, carbon-dopedsilicon nitride, or a combination thereof.

As described throughout the present application, gate lines or gatestructures may be composed of a gate electrode stack which includes agate dielectric layer and a gate electrode layer. In an embodiment, thegate electrode of the gate electrode stack is composed of a metal gateand the gate dielectric layer is composed of a high-K material. Forexample, in one embodiment, the gate dielectric layer is composed of amaterial such as, but not limited to, hafnium oxide, hafniumoxy-nitride, hafnium silicate, lanthanum oxide, zirconium oxide,zirconium silicate, tantalum oxide, barium strontium titanate, bariumtitanate, strontium titanate, yttrium oxide, aluminum oxide, leadscandium tantalum oxide, lead zinc niobate, or a combination thereof.Furthermore, a portion of gate dielectric layer may include a layer ofnative oxide formed from the top few layers of a semiconductorsubstrate. In an embodiment, the gate dielectric layer is composed of atop high-k portion and a lower portion composed of an oxide of asemiconductor material. In one embodiment, the gate dielectric layer iscomposed of a top portion of hafnium oxide and a bottom portion ofsilicon dioxide or silicon oxy-nitride. In some implementations, aportion of the gate dielectric is a “U”-shaped structure that includes abottom portion substantially parallel to the surface of the substrateand two sidewall portions that are substantially perpendicular to thetop surface of the substrate.

In one embodiment, a gate electrode is composed of a metal layer suchas, but not limited to, metal nitrides, metal carbides, metal silicides,metal aluminides, hafnium, zirconium, titanium, tantalum, aluminum,ruthenium, palladium, platinum, cobalt, nickel or conductive metaloxides. In a specific embodiment, the gate electrode is composed of anon-workfunction-setting fill material formed above a metalworkfunction-setting layer. The gate electrode layer may consist of aP-type workfunction metal or an N-type workfunction metal, depending onwhether the transistor is to be a PMOS or an NMOS transistor. In someimplementations, the gate electrode layer may consist of a stack of twoor more metal layers, where one or more metal layers are workfunctionmetal layers and at least one metal layer is a conductive fill layer.For a PMOS transistor, metals that may be used for the gate electrodeinclude, but are not limited to, ruthenium, palladium, platinum, cobalt,nickel, and conductive metal oxides, e.g., ruthenium oxide. A P-typemetal layer will enable the formation of a PMOS gate electrode with aworkfunction that is between about 4.9 eV and about 5.2 eV. For an NMOStransistor, metals that may be used for the gate electrode include, butare not limited to, hafnium, zirconium, titanium, tantalum, aluminum,alloys of these metals, and carbides of these metals such as hafniumcarbide, zirconium carbide, titanium carbide, tantalum carbide, andaluminum carbide. An N-type metal layer will enable the formation of anNMOS gate electrode with a workfunction that is between about 3.9 eV andabout 4.2 eV. In some implementations, the gate electrode may consist ofa “U”-shaped structure that includes a bottom portion substantiallyparallel to the surface of the substrate and two sidewall portions thatare substantially perpendicular to the top surface of the substrate. Inanother implementation, at least one of the metal layers that form thegate electrode may simply be a planar layer that is substantiallyparallel to the top surface of the substrate and does not includesidewall portions substantially perpendicular to the top surface of thesubstrate. In further implementations of the disclosure, the gateelectrode may consist of a combination of U-shaped structures andplanar, non-U-shaped structures. For example, the gate electrode mayconsist of one or more U-shaped metal layers formed atop one or moreplanar, non-U-shaped layers.

As described throughout the present application, spacers associated withgate lines or electrode stacks may be composed of a material suitable toultimately electrically isolate, or contribute to the isolation of, apermanent gate structure from adjacent conductive contacts, such asself-aligned contacts. For example, in one embodiment, the spacers arecomposed of a dielectric material such as, but not limited to, silicondioxide, silicon oxy-nitride, silicon nitride, or carbon-doped siliconnitride.

In an embodiment, as used throughout the present description, interlayerdielectric (ILD) material is composed of or includes a layer of adielectric or insulating material. Examples of suitable dielectricmaterials include, but are not limited to, oxides of silicon (e.g.,silicon dioxide (SiO₂)), doped oxides of silicon, fluorinated oxides ofsilicon, carbon doped oxides of silicon, various low-k dielectricmaterials known in the arts, and combinations thereof. The interlayerdielectric material may be formed by techniques, such as, for example,chemical vapor deposition (CVD), physical vapor deposition (PVD), or byother deposition methods.

In an embodiment, as is also used throughout the present description,metal lines or interconnect line material (and via material) is composedof one or more metal or other conductive structures. A common example isthe use of copper lines and structures that may or may not includebarrier layers between the copper and surrounding ILD material. As usedherein, the term metal includes alloys, stacks, and other combinationsof multiple metals. For example, the metal interconnect lines mayinclude barrier layers (e.g., layers including one or more of Ta, TaN,Ti or TiN), stacks of different metals or alloys, etc. Thus, theinterconnect lines may be a single material layer, or may be formed fromseveral layers, including conductive liner layers and fill layers. Anysuitable deposition process, such as electroplating, chemical vapordeposition or physical vapor deposition, may be used to forminterconnect lines. In an embodiment, the interconnect lines arecomposed of a conductive material such as, but not limited to, Cu, Al,Ti, Zr, Hf, V, Ru, Co, Ni, Pd, Pt, W, Ag, Au or alloys thereof. Theinterconnect lines are also sometimes referred to in the art as traces,wires, lines, metal, or simply interconnect.

In an embodiment, as is also used throughout the present description,hardmask materials are composed of dielectric materials different fromthe interlayer dielectric material. In one embodiment, differenthardmask materials may be used in different regions so as to providedifferent growth or etch selectivity to each other and to the underlyingdielectric and metal layers. In some embodiments, a hardmask layerincludes a layer of a nitride of silicon (e.g., silicon nitride) or alayer of an oxide of silicon, or both, or a combination thereof. Othersuitable materials may include carbon-based materials. In anotherembodiment, a hardmask material includes a metal species. For example, ahardmask or other overlying material may include a layer of a nitride oftitanium or another metal (e.g., titanium nitride). Potentially lesseramounts of other materials, such as oxygen, may be included in one ormore of these layers. Alternatively, other hardmask layers known in thearts may be used depending upon the particular implementation. Thehardmask layers maybe formed by CVD, PVD, or by other depositionmethods.

In an embodiment, as is also used throughout the present description,lithographic operations are performed using 193 nm immersion lithography(i193), extreme ultra-violet (EUV) lithography or electron beam directwrite (EBDW) lithography, or the like. A positive tone or a negativetone resist may be used. In one embodiment, a lithographic mask is atrilayer mask composed of a topographic masking portion, ananti-reflective coating (ARC) layer, and a photoresist layer. In aparticular such embodiment, the topographic masking portion is a carbonhardmask (CHM) layer and the anti-reflective coating layer is a siliconARC layer.

In an embodiment, approaches described herein may involve formation of acontact pattern which is very well aligned to an existing gate patternwhile eliminating the use of a lithographic operation with exceedinglytight registration budget. In one such embodiment, this approach enablesthe use of intrinsically highly selective wet etching (e.g., versus dryor plasma etching) to generate contact openings. In an embodiment, acontact pattern is formed by utilizing an existing gate pattern incombination with a contact plug lithography operation. In one suchembodiment, the approach enables elimination of the need for anotherwise critical lithography operation to generate a contact pattern,as used in other approaches. In an embodiment, a trench contact grid isnot separately patterned, but is rather formed between poly (gate)lines. For example, in one such embodiment, a trench contact grid isformed subsequent to gate grating patterning but prior to gate gratingcuts.

Furthermore, a gate stack structure may be fabricated by a replacementgate process. In such a scheme, dummy gate material such as polysiliconor silicon nitride pillar material, may be removed and replaced withpermanent gate electrode material. In one such embodiment, a permanentgate dielectric layer is also formed in this process, as opposed tobeing carried through from earlier processing. In an embodiment, dummygates are removed by a dry etch or wet etch process. In one embodiment,dummy gates are composed of polycrystalline silicon or amorphous siliconand are removed with a dry etch process including use of SF₆. In anotherembodiment, dummy gates are composed of polycrystalline silicon oramorphous silicon and are removed with a wet etch process including useof aqueous NH₄OH or tetramethylammonium hydroxide. In one embodiment,dummy gates are composed of silicon nitride and are removed with a wetetch including aqueous phosphoric acid.

In an embodiment, one or more approaches described herein contemplateessentially a dummy and replacement gate process in combination with adummy and replacement contact process to arrive at structure. In onesuch embodiment, the replacement contact process is performed after thereplacement gate process to allow high temperature anneal of at least aportion of the permanent gate stack. For example, in a specific suchembodiment, an anneal of at least a portion of the permanent gatestructures, e.g., after a gate dielectric layer is formed, is performedat a temperature greater than approximately 600 degrees Celsius. Theanneal is performed prior to formation of the permanent contacts.

In some embodiments, the arrangement of a semiconductor structure ordevice places a gate contact over portions of a gate line or gate stackover isolation regions. However, such an arrangement may be viewed asinefficient use of layout space. In another embodiment, a semiconductordevice has contact structures that contact portions of a gate electrodeformed over an active region. In general, prior to (e.g., in additionto) forming a gate contact structure (such as a via) over an activeportion of a gate and in a same layer as a trench contact via, one ormore embodiments of the present disclosure include first using a gatealigned trench contact process. Such a process may be implemented toform trench contact structures for semiconductor structure fabrication,e.g., for integrated circuit fabrication. In an embodiment, a trenchcontact pattern is formed as aligned to an existing gate pattern. Bycontrast, other approaches typically involve an additional lithographyprocess with tight registration of a lithographic contact pattern to anexisting gate pattern in combination with selective contact etches. Forexample, another process may include patterning of a poly (gate) gridwith separate patterning of contact features.

It is to be appreciated that pitch division processing and patterningschemes may be implemented to enable embodiments described herein or maybe included as part of embodiments described herein. Pitch divisionpatterning typically refers to pitch halving, pitch quartering etc.Pitch division schemes may be applicable to FEOL processing, BEOLprocessing, or both FEOL (device) and BEOL (metallization) processing.In accordance with one or more embodiments described herein, opticallithography is first implemented to print unidirectional lines (e.g.,either strictly unidirectional or predominantly unidirectional) in apre-defined pitch. Pitch division processing is then implemented as atechnique to increase line density.

In an embodiment, the term “grating structure” for fins, gate lines,metal lines, ILD lines or hardmask lines is used herein to refer to atight pitch grating structure. In one such embodiment, the tight pitchis not achievable directly through a selected lithography. For example,a pattern based on a selected lithography may first be formed, but thepitch may be halved by the use of spacer mask patterning, as is known inthe art. Even further, the original pitch may be quartered by a secondround of spacer mask patterning. Accordingly, the grating-like patternsdescribed herein may have metal lines, ILD lines or hardmask linesspaced at a substantially consistent pitch and having a substantiallyconsistent width. For example, in some embodiments the pitch variationwould be within ten percent and the width variation would be within tenpercent, and in some embodiments, the pitch variation would be withinfive percent and the width variation would be within five percent. Thepattern may be fabricated by a pitch halving or pitch quartering, orother pitch division, approach. In an embodiment, the grating is notnecessarily single pitch.

In an embodiment, a blanket film is patterned using lithography and etchprocessing which may involve, e.g., spacer-based-double-patterning(SBDP) or pitch halving, or spacer-based-quadruple-patterning (SBQP) orpitch quartering. It is to be appreciated that other pitch divisionapproaches may also be implemented. In any case, in an embodiment, agridded layout may be fabricated by a selected lithography approach,such as 193 nm immersion lithography (193i). Pitch division may beimplemented to increase the density of lines in the gridded layout by afactor of n. Gridded layout formation with 193i lithography plus pitchdivision by a factor of ‘n’ can be designated as 193i+P/n PitchDivision. In one such embodiment, 193 nm immersion scaling can beextended for many generations with cost effective pitch division.

It is also to be appreciated that not all aspects of the processesdescribed above need be practiced to fall within the spirit and scope ofembodiments of the present disclosure. For example, in one embodiment,dummy gates need not ever be formed prior to fabricating gate contactsover active portions of the gate stacks. The gate stacks described abovemay actually be permanent gate stacks as initially formed. Also, theprocesses described herein may be used to fabricate one or a pluralityof semiconductor devices. The semiconductor devices may be transistorsor like devices. For example, in an embodiment, the semiconductordevices are a metal-oxide semiconductor (MOS) transistors for logic ormemory, or are bipolar transistors. Also, in an embodiment, thesemiconductor devices have a three-dimensional architecture, such as atrigate device, an independently accessed double gate device, or aFIN-FET. One or more embodiments may be particularly useful forfabricating semiconductor devices at a 10 nanometer (10 nm) technologynode sub-10 nanometer (10 nm) technology node.

Additional or intermediate operations for FEOL layer or structurefabrication may include standard microelectronic fabrication processessuch as lithography, etch, thin films deposition, planarization (such aschemical mechanical polishing (CMP)), diffusion, metrology, the use ofsacrificial layers, the use of etch stop layers, the use ofplanarization stop layers, or any other associated action withmicroelectronic component fabrication. Also, it is to be appreciatedthat the process operations described for the preceding process flowsmay be practiced in alternative sequences, not every operation need beperformed or additional process operations may be performed, or both.

Embodiments disclosed herein may be used to manufacture a wide varietyof different types of integrated circuits or microelectronic devices.Examples of such integrated circuits include, but are not limited to,processors, chipset components, graphics processors, digital signalprocessors, micro-controllers, and the like. In other embodiments,semiconductor memory may be manufactured. Moreover, the integratedcircuits or other microelectronic devices may be used in a wide varietyof electronic devices known in the arts. For example, in computersystems (e.g., desktop, laptop, server), cellular phones, personalelectronics, etc. The integrated circuits may be coupled with a bus andother components in the systems. For example, a processor may be coupledby one or more buses to a memory, a chipset, etc. Each of the processor,the memory, and the chipset, may potentially be manufactured using theapproaches disclosed herein.

FIG. 9 illustrates a computing device 900 in accordance with oneimplementation of the disclosure. The computing device 900 houses aboard 902. The board 902 may include a number of components, includingbut not limited to a processor 904 and at least one communication chip906. The processor 904 is physically and electrically coupled to theboard 902. In some implementations the at least one communication chip906 is also physically and electrically coupled to the board 902. Infurther implementations, the communication chip 906 is part of theprocessor 904.

Depending on its applications, computing device 900 may include othercomponents that may or may not be physically and electrically coupled tothe board 902. These other components include, but are not limited to,volatile memory (e.g., DRAM), non-volatile memory (e.g., ROM), flashmemory, a graphics processor, a digital signal processor, a cryptoprocessor, a chipset, an antenna, a display, a touchscreen display, atouchscreen controller, a battery, an audio codec, a video codec, apower amplifier, a global positioning system (GPS) device, a compass, anaccelerometer, a gyroscope, a speaker, a camera, and a mass storagedevice (such as hard disk drive, compact disk (CD), digital versatiledisk (DVD), and so forth).

The communication chip 906 enables wireless communications for thetransfer of data to and from the computing device 900. The term“wireless” and its derivatives may be used to describe circuits,devices, systems, methods, techniques, communications channels, etc.,that may communicate data through the use of modulated electromagneticradiation through a non-solid medium. The term does not imply that theassociated devices do not contain any wires, although in someembodiments they might not. The communication chip 906 may implement anyof a number of wireless standards or protocols, including but notlimited to Wi-Fi (IEEE 802.11 family), WiMAX (IEEE 802.16 family), IEEE802.20, long term evolution (LTE), Ev-DO, HSPA+, HSDPA+, HSUPA+, EDGE,GSM, GPRS, CDMA, TDMA, DECT, Bluetooth, derivatives thereof, as well asany other wireless protocols that are designated as 3G, 4G, 5G, andbeyond. The computing device 900 may include a plurality ofcommunication chips 906. For instance, a first communication chip 906may be dedicated to shorter range wireless communications such as Wi-Fiand Bluetooth and a second communication chip 906 may be dedicated tolonger range wireless communications such as GPS, EDGE, GPRS, CDMA,WiMAX, LTE, Ev-DO, and others.

The processor 904 of the computing device 900 includes an integratedcircuit die packaged within the processor 904. In some implementationsof embodiments of the disclosure, the integrated circuit die of theprocessor includes one or more structures, such as integrated circuitstructures built in accordance with implementations of the disclosure.The term “processor” may refer to any device or portion of a device thatprocesses electronic data from registers or memory to transform thatelectronic data, or both, into other electronic data that may be storedin registers or memory, or both.

The communication chip 906 also includes an integrated circuit diepackaged within the communication chip 906. In accordance with anotherimplementation of the disclosure, the integrated circuit die of thecommunication chip is built in accordance with implementations of thedisclosure.

In further implementations, another component housed within thecomputing device 900 may contain an integrated circuit die built inaccordance with implementations of embodiments of the disclosure.

In various embodiments, the computing device 900 may be a laptop, anetbook, a notebook, an ultrabook, a smartphone, a tablet, a personaldigital assistant (PDA), an ultramobile PC, a mobile phone, a desktopcomputer, a server, a printer, a scanner, a monitor, a set-top box, anentertainment control unit, a digital camera, a portable music player,or a digital video recorder. In further implementations, the computingdevice 900 may be any other electronic device that processes data.

FIG. 10 illustrates an interposer 1000 that includes one or moreembodiments of the disclosure. The interposer 1000 is an interveningsubstrate used to bridge a first substrate 1002 to a second substrate1004. The first substrate 1002 may be, for instance, an integratedcircuit die. The second substrate 1004 may be, for instance, a memorymodule, a computer motherboard, or another integrated circuit die.Generally, the purpose of an interposer 1000 is to spread a connectionto a wider pitch or to reroute a connection to a different connection.For example, an interposer 1000 may couple an integrated circuit die toa ball grid array (BGA) 1006 that can subsequently be coupled to thesecond substrate 1004. In some embodiments, the first and secondsubstrates 1002/1004 are attached to opposing sides of the interposer1000. In other embodiments, the first and second substrates 1002/1004are attached to the same side of the interposer 1000. And in furtherembodiments, three or more substrates are interconnected by way of theinterposer 1000.

The interposer 1000 may be formed of an epoxy resin, afiberglass-reinforced epoxy resin, a ceramic material, or a polymermaterial such as polyimide. In further implementations, the interposermay be formed of alternate rigid or flexible materials that may includethe same materials described above for use in a semiconductor substrate,such as silicon, germanium, and other group III-V and group IVmaterials.

The interposer may include metal interconnects 1008 and vias 1010,including but not limited to through-silicon vias (TSVs) 1012. Theinterposer 1000 may further include embedded devices 1014, includingboth passive and active devices. Such devices include, but are notlimited to, capacitors, decoupling capacitors, resistors, inductors,fuses, diodes, transformers, sensors, and electrostatic discharge (ESD)devices. More complex devices such as radio-frequency (RF) devices,power amplifiers, power management devices, antennas, arrays, sensors,and MEMS devices may also be formed on the interposer 8000. Inaccordance with embodiments of the disclosure, apparatuses or processesdisclosed herein may be used in the fabrication of interposer 1000 or inthe fabrication of components included in the interposer 1000.

FIG. 11 is an isometric view of a mobile computing platform 1100employing an integrated circuit (IC) fabricated according to one or moreprocesses described herein or including one or more features describedherein, in accordance with an embodiment of the present disclosure.

The mobile computing platform 1100 may be any portable device configuredfor each of electronic data display, electronic data processing, andwireless electronic data transmission. For example, mobile computingplatform 1100 may be any of a tablet, a smart phone, laptop computer,etc. and includes a display screen 1105 which in the exemplaryembodiment is a touchscreen (capacitive, inductive, resistive, etc.), achip-level (SoC) or package-level integrated system 1110, and a battery1113. As illustrated, the greater the level of integration in the system1110 enabled by higher transistor packing density, the greater theportion of the mobile computing platform 1100 that may be occupied bythe battery 1113 or non-volatile storage, such as a solid state drive,or the greater the transistor gate count for improved platformfunctionality. Similarly, the greater the carrier mobility of eachtransistor in the system 1110, the greater the functionality. As such,techniques described herein may enable performance and form factorimprovements in the mobile computing platform 1100.

The integrated system 1110 is further illustrated in the expanded view1120. In the exemplary embodiment, packaged device 1177 includes atleast one memory chip (e.g., RAM), or at least one processor chip (e.g.,a multi-core microprocessor and/or graphics processor) fabricatedaccording to one or more processes described herein or including one ormore features described herein. The packaged device 1177 is furthercoupled to the board 1160 along with one or more of a power managementintegrated circuit (PMIC) 1115, RF (wireless) integrated circuit (RFIC)1125 including a wideband RF (wireless) transmitter and/or receiver(e.g., including a digital baseband and an analog front end modulefurther includes a power amplifier on a transmit path and a low noiseamplifier on a receive path), and a controller thereof 1111.Functionally, the PMIC 1115 performs battery power regulation, DC-to-DCconversion, etc., and so has an input coupled to the battery 1113 andwith an output providing a current supply to all the other functionalmodules. As further illustrated, in the exemplary embodiment, the RFIC1125 has an output coupled to an antenna to provide to implement any ofa number of wireless standards or protocols, including but not limitedto Wi-Fi (IEEE 802.11 family), WiMAX (IEEE 802.16 family), IEEE 802.20,long term evolution (LTE), Ev-DO, HSPA+, HSDPA+, HSUPA+, EDGE, GSM,GPRS, CDMA, TDMA, DECT, Bluetooth, derivatives thereof, as well as anyother wireless protocols that are designated as 3G, 4G, 5G, and beyond.In alternative implementations, each of these board-level modules may beintegrated onto separate ICs coupled to the package substrate of thepackaged device 1177 or within a single IC (SoC) coupled to the packagesubstrate of the packaged device 1177.

In another aspect, semiconductor packages are used for protecting anintegrated circuit (IC) chip or die, and also to provide the die with anelectrical interface to external circuitry. With the increasing demandfor smaller electronic devices, semiconductor packages are designed tobe even more compact and must support larger circuit density.Furthermore, the demand for higher performance devices results in a needfor an improved semiconductor package that enables a thin packagingprofile and low overall warpage compatible with subsequent assemblyprocessing.

In an embodiment, wire bonding to a ceramic or organic package substrateis used. In another embodiment, a C4 process is used to mount a die to aceramic or organic package substrate. In particular, C4 solder ballconnections can be implemented to provide flip chip interconnectionsbetween semiconductor devices and substrates. A flip chip or ControlledCollapse Chip Connection (C4) is a type of mounting used forsemiconductor devices, such as integrated circuit (IC) chips, MEMS orcomponents, which utilizes solder bumps instead of wire bonds. Thesolder bumps are deposited on the C4 pads, located on the top side ofthe substrate package. In order to mount the semiconductor device to thesubstrate, it is flipped over with the active side facing down on themounting area. The solder bumps are used to connect the semiconductordevice directly to the substrate.

FIG. 12 illustrates a cross-sectional view of a flip-chip mounted die,in accordance with an embodiment of the present disclosure.

Referring to FIG. 12, an apparatus 1200 includes a die 1202 such as anintegrated circuit (IC) fabricated according to one or more processesdescribed herein or including one or more features described herein, inaccordance with an embodiment of the present disclosure. The die 1202includes metallized pads 1204 thereon. A package substrate 1206, such asa ceramic or organic substrate, includes connections 1208 thereon. Thedie 1202 and package substrate 1206 are electrically connected by solderballs 1210 coupled to the metallized pads 1204 and the connections 1208.An underfill material 1212 surrounds the solder balls 1210.

Processing a flip chip may be similar to conventional IC fabrication,with a few additional operations. Near the end of the manufacturingprocess, the attachment pads are metalized to make them more receptiveto solder. This typically consists of several treatments. A small dot ofsolder is then deposited on each metalized pad. The chips are then cutout of the wafer as normal. To attach the flip chip into a circuit, thechip is inverted to bring the solder dots down onto connectors on theunderlying electronics or circuit board. The solder is then re-melted toproduce an electrical connection, typically using an ultrasonic oralternatively reflow solder process. This also leaves a small spacebetween the chip's circuitry and the underlying mounting. In most casesan electrically-insulating adhesive is then “underfilled” to provide astronger mechanical connection, provide a heat bridge, and to ensure thesolder joints are not stressed due to differential heating of the chipand the rest of the system.

In other embodiments, newer packaging and die-to-die interconnectapproaches, such as through silicon via (TSV) and silicon interposer,are implemented to fabricate high performance Multi-Chip Module (MCM)and System in Package (SiP) incorporating an integrated circuit (IC)fabricated according to one or more processes described herein orincluding one or more features described herein, in accordance with anembodiment of the present disclosure.

Thus, embodiments of the present disclosure include contact over activegate (COAG) structures with etch stop layers, and methods of fabricatingcontact over active gate (COAG) structures using etch stop layers.

Although specific embodiments have been described above, theseembodiments are not intended to limit the scope of the presentdisclosure, even where only a single embodiment is described withrespect to a particular feature. Examples of features provided in thedisclosure are intended to be illustrative rather than restrictiveunless stated otherwise. The above description is intended to cover suchalternatives, modifications, and equivalents as would be apparent to aperson skilled in the art having the benefit of the present disclosure.

The scope of the present disclosure includes any feature or combinationof features disclosed herein (either explicitly or implicitly), or anygeneralization thereof, whether or not it mitigates any or all of theproblems addressed herein. Accordingly, new claims may be formulatedduring prosecution of the present application (or an applicationclaiming priority thereto) to any such combination of features. Inparticular, with reference to the appended claims, features fromdependent claims may be combined with those of the independent claimsand features from respective independent claims may be combined in anyappropriate manner and not merely in the specific combinationsenumerated in the appended claims.

The following examples pertain to further embodiments. The variousfeatures of the different embodiments may be variously combined withsome features included and others excluded to suit a variety ofdifferent applications.

Example embodiment 1: An integrated circuit structure includes aplurality of gate structures above substrate, each of the gatestructures including a gate insulating layer thereon. A plurality ofconductive trench contact structures is alternating with the pluralityof gate structures, each of the conductive trench contact structuresincluding a trench insulating layer thereon. A first dielectric etchstop layer is directly on and continuous over the trench insulatinglayers and the gate insulating layers. A second dielectric etch stoplayer is directly on and continuous over the first dielectric etch stoplayer, the second dielectric etch stop layer distinct from the firstdielectric etch stop layer. An interlayer dielectric material is on thesecond dielectric etch stop layer. An opening is in the interlayerdielectric material, in the second dielectric etch stop layer, in thefirst dielectric etch stop layer, and in one of the trench insulatinglayers. A conductive structure is in the opening, the conductivestructure in direct contact with a corresponding one of the trenchcontact structures.

Example embodiment 2: The integrated circuit structure of exampleembodiment 1, wherein the second dielectric etch stop layer includesaluminum and oxygen.

Example embodiment 3: The integrated circuit structure of exampleembodiment 1 or 2, wherein the first etch stop layer includes nitrogen,silicon and hydrogen.

Example embodiment 4: The integrated circuit structure of exampleembodiment 1, 2 or 3, wherein the interlayer dielectric materialincludes silicon, oxygen, carbon and hydrogen.

Example embodiment 5: The integrated circuit structure of exampleembodiment 1, 2, 3 or 4, wherein the trench insulating layers includesilicon carbide, and the gate insulating layers include silicon nitride.

Example embodiment 6: The integrated circuit structure of exampleembodiment 1, 2, 3, 4 or 5, further including a plurality of dielectricspacers alternating with the plurality of gate structures and theplurality of conductive trench contact structures, wherein the firstdielectric etch stop layer is directly on the plurality of dielectricspacers.

Example embodiment 7: The integrated circuit structure of exampleembodiment 1, 2, 3, 4, 5 or 6, wherein the plurality of conductivetrench contact structures and the plurality of gate structures are on asemiconductor fin.

Example embodiment 8: The integrated circuit structure of exampleembodiment 1, 2, 3, 4, 5, 6 or 7, wherein the conductive structureincludes an upper conductive line and a lower conductive via.

Example embodiment 9: An integrated circuit structure includes aplurality of gate structures above substrate, each of the gatestructures including a gate insulating layer thereon. A plurality ofconductive trench contact structures is alternating with the pluralityof gate structures, each of the conductive trench contact structuresincluding a trench insulating layer thereon. A first dielectric etchstop layer is directly on and continuous over the trench insulatinglayers and the gate insulating layers. A second dielectric etch stoplayer is directly on and continuous over the first dielectric etch stoplayer, the second dielectric etch stop layer distinct from the firstdielectric etch stop layer. An interlayer dielectric material is on thesecond dielectric etch stop layer. An opening is in the interlayerdielectric material, in the second dielectric etch stop layer, in thefirst dielectric etch stop layer, and in one of the gate insulatinglayers. A conductive structure is in the opening, the conductivestructure in direct contact with a corresponding one of the gatestructures.

Example embodiment 10: The integrated circuit structure of exampleembodiment 9, wherein the second dielectric etch stop layer includesaluminum and oxygen.

Example embodiment 11: The integrated circuit structure of exampleembodiment 9 or 10, wherein the first etch stop layer includes nitrogen,silicon and hydrogen.

Example embodiment 12: The integrated circuit structure of exampleembodiment 9, 10 or 11, wherein the interlayer dielectric materialincludes silicon, oxygen, carbon and hydrogen.

Example embodiment 13: The integrated circuit structure of exampleembodiment 9, 10, 11 or 12, wherein the trench insulating layers includesilicon carbide, and the gate insulating layers include silicon nitride.

Example embodiment 14: The integrated circuit structure of exampleembodiment 9, 10, 11, 12 or 13, further including a plurality ofdielectric spacers alternating with the plurality of gate structures andthe plurality of conductive trench contact structures, wherein the firstdielectric etch stop layer is directly on the plurality of dielectricspacers.

Example embodiment 15: The integrated circuit structure of exampleembodiment 9, 10, 11, 12, 13 or 14, wherein the plurality of conductivetrench contact structures and the plurality of gate structures are on asemiconductor fin.

Example embodiment 16: The integrated circuit structure of exampleembodiment 9, 10, 11, 12, 13, 14 or 15, wherein the conductive structureincludes an upper conductive line and a lower conductive via.

Example embodiment 17: A method of fabricating an integrated circuitstructure includes forming a plurality of gate structures abovesubstrate, each of the gate structures including a gate insulating layerthereon. The method also includes forming a plurality of conductivetrench contact structures alternating with the plurality of gatestructures, each of the conductive trench contact structures including atrench insulating layer thereon. The method also includes forming afirst dielectric etch stop layer directly on and continuous over thetrench insulating layers and the gate insulating layers. The method alsoincludes forming a second dielectric etch stop layer directly on andcontinuous over the first dielectric etch stop layer, the seconddielectric etch stop layer distinct from the first dielectric etch stoplayer. The method also includes forming an interlayer dielectricmaterial on the second dielectric etch stop layer. The method alsoincludes forming an opening in the interlayer dielectric material usinga first dry or plasma etch process. The method also includes extendingthe opening in the second dielectric etch stop layer using a wet etchprocess. The method also includes further extending the opening in thefirst dielectric etch stop layer and in one of the trench insulatinglayers using a second dry or plasma etch process. The method alsoincludes forming a conductive structure in the opening, the conductivestructure in direct contact with a corresponding one of the trenchcontact structures.

Example embodiment 18: The method of example embodiment 17, wherein thesecond dielectric etch stop layer includes aluminum and oxygen.

Example embodiment 19: The method of example embodiment 17 or 18,wherein the first etch stop layer includes nitrogen, silicon andhydrogen.

Example embodiment 20: The method of example embodiment 17, 18 or 19,wherein the interlayer dielectric material includes silicon, oxygen,carbon and hydrogen, and wherein the trench insulating layers includesilicon carbide.

Example embodiment 21: A method of fabricating an integrated circuitstructure includes forming a plurality of gate structures abovesubstrate, each of the gate structures including a gate insulating layerthereon. The method also includes forming a plurality of conductivetrench contact structures alternating with the plurality of gatestructures, each of the conductive trench contact structures including atrench insulating layer thereon. The method also includes forming afirst dielectric etch stop layer directly on and continuous over thetrench insulating layers and the gate insulating layers. The method alsoincludes forming a second dielectric etch stop layer directly on andcontinuous over the first dielectric etch stop layer, the seconddielectric etch stop layer distinct from the first dielectric etch stoplayer. The method also includes forming an interlayer dielectricmaterial on the second dielectric etch stop layer. The method alsoincludes forming an opening in the interlayer dielectric material usinga first dry or plasma etch process. The method also includes extendingthe opening in the second dielectric etch stop layer using a wet etchprocess. The method also includes further extending the opening in thefirst dielectric etch stop layer and in one of the gate insulatinglayers using a second dry or plasma etch process. The method alsoincludes forming a conductive structure in the opening, the conductivestructure in direct contact with a corresponding one of the gatestructures.

Example embodiment 22: The method of example embodiment 21, wherein thesecond dielectric etch stop layer includes aluminum and oxygen.

Example embodiment 23: The method of example embodiment 21 or 22,wherein the first etch stop layer includes nitrogen, silicon andhydrogen.

Example embodiment 24: The method of example embodiment 21, 22 or 23,wherein the interlayer dielectric material includes silicon, oxygen,carbon and hydrogen, and wherein the gate insulating layers includesilicon nitride.

What is claimed is:
 1. An integrated circuit structure, comprising: aplurality of gate structures above substrate, each of the gatestructures including a gate insulating layer thereon; a plurality ofconductive trench contact structures alternating with the plurality ofgate structures, each of the conductive trench contact structuresincluding a trench insulating layer thereon; a first dielectric etchstop layer directly on and continuous over the trench insulating layersand the gate insulating layers; a second dielectric etch stop layerdirectly on and continuous over the first dielectric etch stop layer,the second dielectric etch stop layer distinct from the first dielectricetch stop layer; an interlayer dielectric material on the seconddielectric etch stop layer; an opening in the interlayer dielectricmaterial, in the second dielectric etch stop layer, in the firstdielectric etch stop layer, and in one of the gate insulating layers;and a conductive structure in the opening, the conductive structure indirect contact with a corresponding one of the gate structures.
 2. Theintegrated circuit structure of claim 1, wherein the second dielectricetch stop layer comprises aluminum and oxygen.
 3. The integrated circuitstructure of claim 1, wherein the first etch stop layer comprisesnitrogen, silicon and hydrogen.
 4. The integrated circuit structure ofclaim 1, wherein the interlayer dielectric material comprises silicon,oxygen, carbon and hydrogen.
 5. The integrated circuit structure ofclaim 1, wherein the trench insulating layers comprise silicon carbide,and the gate insulating layers comprise silicon nitride.
 6. Theintegrated circuit structure of claim 1, further comprising: a pluralityof dielectric spacers alternating with the plurality of gate structuresand the plurality of conductive trench contact structures, wherein thefirst dielectric etch stop layer is directly on the plurality ofdielectric spacers.
 7. The integrated circuit structure of claim 1,wherein the plurality of conductive trench contact structures and theplurality of gate structures are on a semiconductor fin.
 8. Theintegrated circuit structure of claim 1, wherein the conductivestructure includes an upper conductive line and a lower conductive via.9. A method of fabricating an integrated circuit structure, the methodcomprising: forming a plurality of gate structures above substrate, eachof the gate structures including a gate insulating layer thereon;forming a plurality of conductive trench contact structures alternatingwith the plurality of gate structures, each of the conductive trenchcontact structures including a trench insulating layer thereon; forminga first dielectric etch stop layer directly on and continuous over thetrench insulating layers and the gate insulating layers; forming asecond dielectric etch stop layer directly on and continuous over thefirst dielectric etch stop layer, the second dielectric etch stop layerdistinct from the first dielectric etch stop layer; forming aninterlayer dielectric material on the second dielectric etch stop layer;forming an opening in the interlayer dielectric material using a firstdry or plasma etch process; extending the opening in the seconddielectric etch stop layer using a wet etch process; further extendingthe opening in the first dielectric etch stop layer and in one of thetrench insulating layers using a second dry or plasma etch process; andforming a conductive structure in the opening, the conductive structurein direct contact with a corresponding one of the trench contactstructures.
 10. The method of claim 9, wherein the second dielectricetch stop layer comprises aluminum and oxygen.
 11. The method of claim9, wherein the first etch stop layer comprises nitrogen, silicon andhydrogen.
 12. The method of claim 11, wherein the interlayer dielectricmaterial comprises silicon, oxygen, carbon and hydrogen, and wherein thetrench insulating layers comprise silicon carbide.
 13. A method offabricating an integrated circuit structure, the method comprising:forming a plurality of gate structures above substrate, each of the gatestructures including a gate insulating layer thereon; forming aplurality of conductive trench contact structures alternating with theplurality of gate structures, each of the conductive trench contactstructures including a trench insulating layer thereon; forming a firstdielectric etch stop layer directly on and continuous over the trenchinsulating layers and the gate insulating layers; forming a seconddielectric etch stop layer directly on and continuous over the firstdielectric etch stop layer, the second dielectric etch stop layerdistinct from the first dielectric etch stop layer; forming aninterlayer dielectric material on the second dielectric etch stop layer;forming an opening in the interlayer dielectric material using a firstdry or plasma etch process; extending the opening in the seconddielectric etch stop layer using a wet etch process; further extendingthe opening in the first dielectric etch stop layer and in one of thegate insulating layers using a second dry or plasma etch process; andforming a conductive structure in the opening, the conductive structurein direct contact with a corresponding one of the gate structures. 14.The method of claim 13, wherein the second dielectric etch stop layercomprises aluminum and oxygen.
 15. The method of claim 13, wherein thefirst etch stop layer comprises nitrogen, silicon and hydrogen.
 16. Themethod of claim 13, wherein the interlayer dielectric material comprisessilicon, oxygen, carbon and hydrogen, and wherein the gate insulatinglayers comprise silicon nitride.
 17. A computing device, comprising: aboard; and a component coupled to the board, the component including anintegrated circuit structure, comprising: a plurality of gate structuresabove substrate, each of the gate structures including a gate insulatinglayer thereon; a plurality of conductive trench contact structuresalternating with the plurality of gate structures, each of theconductive trench contact structures including a trench insulating layerthereon; a first dielectric etch stop layer directly on and continuousover the trench insulating layers and the gate insulating layers; asecond dielectric etch stop layer directly on and continuous over thefirst dielectric etch stop layer, the second dielectric etch stop layerdistinct from the first dielectric etch stop layer; an interlayerdielectric material on the second dielectric etch stop layer; an openingin the interlayer dielectric material, in the second dielectric etchstop layer, in the first dielectric etch stop layer, and in one of thegate insulating layers; and a conductive structure in the opening, theconductive structure in direct contact with a corresponding one of thegate structures.
 18. The computing device of claim 17, furthercomprising: a memory coupled to the board.
 20. The computing device ofclaim 17, further comprising: a communication chip coupled to the board.21. The computing device of claim 17, wherein the component is apackaged integrated circuit die.
 22. The computing device of claim 17,wherein the component is selected from the group consisting of aprocessor, a communications chip, and a digital signal processor.